Monday, November 23, 2015

Season 8 superfinal, games 41-50

After 50 games, at the halfway point of the Komodo-Stockfish superfinal match, Komodo is leading 4-1 with 45 draws. Komodo increased its lead with another win, the chances of a Stockfish comeback are getting really low.

Game 41 got into an interesting imbalance where Komodo was down B vs RP but Stockfish couldn't castle and had badly placed pieces. At one stage Stockfish turned down a repetition twice, but had to give the exchange back. It still had a passed pawn but with the king exposed to queen attacks the game still ended in a draw. There were a few moves in game 42 where Komodo had a small eval advantage as black, but it faded quickly back to 0 and another draw, nothing to get excited about.

In game 43 Komodo kept a small eval advantage but could not realize it on the board. Evals came back to zero as the pieces came off the board, yet another draw. Game 44 featured almost 90 moves of shuffling in a RRB vs RRN position blocked by pawns, close to eight hours of waiting for the final draw.

Game 45 started with a small eval advantage for Komodo, but the evals soon dropped to zero, and this time the game ended quickly in a repetition. In game 46 all the pawns stayed on the board with the queen side blocked. Komodo gradually increased its eval with a little more space on the king side.

After some piece shuffling Komodo was able to realize its advantage by taking a pawn after the queens were exchanged.

Stockfish tried to trade pieces, eventually reaching an opposite color bishop ending with a pawn down, usually a sure draw.

However, in this position Komodo could hold the white king to defend the h pawn, and its king could walk safely to the queen side and attack the pawns there. Stockfish sttacked the black pawns on the king side with its bishop, still only one pawn down, but Komodo's pawns were better placed in the end.

Another win for Komodo, again in black, with opposite color bishops. Inconceivable! You get the feeling that Komodo is just better than Stockfish in this match.

In game 47 Komodo built an eval advantage which turned into an ending of BB vs BN. Stockfish had a beautiful defense, look at the position:

It's a bit like checkers. The light square bishop cannot penetrate, only be exchanged, and the dark square bishop can't do anything to white pieces. After a lot of shuffling Komodo exchanged a bishop for the knight, and for a few moves its evals shot up. It was a false alarm since although Komodo got to queen a pawn first, the only thing the queen was good for was stopping Stockfish from queening as well.

In game 48 Stockfish had two bishops and Komodo two knights, but all the rooks stayed on the board. This made the game much more drawish and it ended faster.

Game 49 was a little wild. Stockfish went for a king side attack, sacrificing two pawns and neglecting to castle. Komodo calmly counterattacked on the queen side, exchanging pieces when possible, then went for a combination that left RBB and pawns vs QN. The kings were so exposed that no progress could be made, so again a draw but at least interesting. Game 50 was also imbalanced, this time Stockfish sacrificed a knight for 3 pawns. Komodo maintained an eval advantage as black and tried to make use of its extra piece. However, by the time it got a pawn back the game was in a 7-man tablebase draw of RN vs RPP, adjudicating a few moves later.